1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
12 extern crate build_helper;
14 use std::process::Command;
16 use std::path::{PathBuf, Path};
18 use build_helper::output;
20 fn detect_llvm_link(llvm_config: &Path) -> (&'static str, Option<&'static str>) {
21 let mut version_cmd = Command::new(llvm_config);
22 version_cmd.arg("--version");
23 let version_output = output(&mut version_cmd);
24 let mut parts = version_output.split('.').take(2)
25 .filter_map(|s| s.parse::<u32>().ok());
26 if let (Some(major), Some(minor)) = (parts.next(), parts.next()) {
27 if major > 3 || (major == 3 && minor >= 9) {
28 // Force the link mode we want, preferring static by default, but
29 // possibly overridden by `configure --enable-llvm-link-shared`.
30 if env::var_os("LLVM_LINK_SHARED").is_some() {
31 return ("dylib", Some("--link-shared"));
33 return ("static", Some("--link-static"));
35 } else if major == 3 && minor == 8 {
36 // Find out LLVM's default linking mode.
37 let mut mode_cmd = Command::new(llvm_config);
38 mode_cmd.arg("--shared-mode");
39 if output(&mut mode_cmd).trim() == "shared" {
40 return ("dylib", None);
42 return ("static", None);
50 let target = env::var("TARGET").expect("TARGET was not set");
51 let llvm_config = env::var_os("LLVM_CONFIG")
54 if let Some(dir) = env::var_os("CARGO_TARGET_DIR").map(PathBuf::from) {
55 let to_test = dir.parent()
60 .join("llvm/bin/llvm-config");
61 if Command::new(&to_test).output().is_ok() {
65 PathBuf::from("llvm-config")
68 println!("cargo:rerun-if-changed={}", llvm_config.display());
70 // Test whether we're cross-compiling LLVM. This is a pretty rare case
71 // currently where we're producing an LLVM for a different platform than
72 // what this build script is currently running on.
74 // In that case, there's no guarantee that we can actually run the target,
75 // so the build system works around this by giving us the LLVM_CONFIG for
76 // the host platform. This only really works if the host LLVM and target
77 // LLVM are compiled the same way, but for us that's typically the case.
79 // We *want* detect this cross compiling situation by asking llvm-config
80 // what it's host-target is. If that's not the TARGET, then we're cross
81 // compiling. Unfortunately `llvm-config` seems either be buggy, or we're
82 // misconfiguring it, because the `i686-pc-windows-gnu` build of LLVM will
83 // report itself with a `--host-target` of `x86_64-pc-windows-gnu`. This
84 // tricks us into thinking we're doing a cross build when we aren't, so
87 // In any case, if we're cross compiling, this generally just means that we
88 // can't trust all the output of llvm-config becaues it might be targeted
89 // for the host rather than the target. As a result a bunch of blocks below
90 // are gated on `if !is_crossed`
91 let target = env::var("TARGET").expect("TARGET was not set");
92 let host = env::var("HOST").expect("HOST was not set");
93 let is_crossed = target != host;
95 let optional_components =
96 ["x86", "arm", "aarch64", "mips", "powerpc", "pnacl", "systemz", "jsbackend", "msp430",
99 // FIXME: surely we don't need all these components, right? Stuff like mcjit
100 // or interpreter the compiler itself never uses.
101 let required_components = &["ipo",
110 let components = output(Command::new(&llvm_config).arg("--components"));
111 let mut components = components.split_whitespace().collect::<Vec<_>>();
112 components.retain(|c| optional_components.contains(c) || required_components.contains(c));
114 for component in required_components {
115 if !components.contains(component) {
116 panic!("require llvm component {} but wasn't found", component);
120 for component in components.iter() {
121 println!("cargo:rustc-cfg=llvm_component=\"{}\"", component);
124 // Link in our own LLVM shims, compiled with the same flags as LLVM
125 let mut cmd = Command::new(&llvm_config);
126 cmd.arg("--cxxflags");
127 let cxxflags = output(&mut cmd);
128 let mut cfg = gcc::Config::new();
129 for flag in cxxflags.split_whitespace() {
130 // Ignore flags like `-m64` when we're doing a cross build
131 if is_crossed && flag.starts_with("-m") {
137 for component in &components[..] {
138 let mut flag = String::from("-DLLVM_COMPONENT_");
139 flag.push_str(&component.to_uppercase());
143 if env::var_os("LLVM_RUSTLLVM").is_some() {
144 cfg.flag("-DLLVM_RUSTLLVM");
147 println!("cargo:rerun-if-changed=../rustllvm/PassWrapper.cpp");
148 println!("cargo:rerun-if-changed=../rustllvm/RustWrapper.cpp");
149 println!("cargo:rerun-if-changed=../rustllvm/ArchiveWrapper.cpp");
150 cfg.file("../rustllvm/PassWrapper.cpp")
151 .file("../rustllvm/RustWrapper.cpp")
152 .file("../rustllvm/ArchiveWrapper.cpp")
154 .cpp_link_stdlib(None) // we handle this below
155 .compile("librustllvm.a");
157 let (llvm_kind, llvm_link_arg) = detect_llvm_link(&llvm_config);
159 // Link in all LLVM libraries, if we're uwring the "wrong" llvm-config then
160 // we don't pick up system libs because unfortunately they're for the host
161 // of llvm-config, not the target that we're attempting to link.
162 let mut cmd = Command::new(&llvm_config);
165 if let Some(link_arg) = llvm_link_arg {
170 cmd.arg("--system-libs");
172 cmd.args(&components[..]);
174 for lib in output(&mut cmd).split_whitespace() {
175 let name = if lib.starts_with("-l") {
177 } else if lib.starts_with("-") {
179 } else if Path::new(lib).exists() {
180 // On MSVC llvm-config will print the full name to libraries, but
181 // we're only interested in the name part
182 let name = Path::new(lib).file_name().unwrap().to_str().unwrap();
183 name.trim_right_matches(".lib")
184 } else if lib.ends_with(".lib") {
185 // Some MSVC libraries just come up with `.lib` tacked on, so chop
187 lib.trim_right_matches(".lib")
192 // Don't need or want this library, but LLVM's CMake build system
193 // doesn't provide a way to disable it, so filter it here even though we
194 // may or may not have built it. We don't reference anything from this
195 // library and it otherwise may just pull in extra dependencies on
196 // libedit which we don't want
197 if name == "LLVMLineEditor" {
201 let kind = if name.starts_with("LLVM") {
206 println!("cargo:rustc-link-lib={}={}", kind, name);
211 // If we're a cross-compile of LLVM then unfortunately we can't trust these
212 // ldflags (largely where all the LLVM libs are located). Currently just
213 // hack around this by replacing the host triple with the target and pray
214 // that those -L directories are the same!
215 let mut cmd = Command::new(&llvm_config);
216 cmd.arg("--ldflags");
217 for lib in output(&mut cmd).split_whitespace() {
218 if lib.starts_with("-LIBPATH:") {
219 println!("cargo:rustc-link-search=native={}", &lib[9..]);
220 } else if is_crossed {
221 if lib.starts_with("-L") {
222 println!("cargo:rustc-link-search=native={}",
223 lib[2..].replace(&host, &target));
225 } else if lib.starts_with("-l") {
226 println!("cargo:rustc-link-lib={}", &lib[2..]);
227 } else if lib.starts_with("-L") {
228 println!("cargo:rustc-link-search=native={}", &lib[2..]);
232 // OpenBSD has a particular C++ runtime library name
233 let stdcppname = if target.contains("openbsd") {
239 // C++ runtime library
240 if !target.contains("msvc") {
241 if let Some(s) = env::var_os("LLVM_STATIC_STDCPP") {
242 assert!(!cxxflags.contains("stdlib=libc++"));
243 let path = PathBuf::from(s);
244 println!("cargo:rustc-link-search=native={}",
245 path.parent().unwrap().display());
246 println!("cargo:rustc-link-lib=static={}", stdcppname);
247 } else if cxxflags.contains("stdlib=libc++") {
248 println!("cargo:rustc-link-lib=c++");
250 println!("cargo:rustc-link-lib={}", stdcppname);